Control system for free stroke piston engines



Dec. 5, 1939. H. STEINE@A M2563 C-ONTROL SYSTEM FOR FREE STROKE PISTON ENGINES Filed April 2, 1956 3 Sheets-Sheet l @nimm/ZS inwards' il.l

ZJSOSS N ENGINES H. STEINER CONTROL SYSTEM FOR FREE STROKE PISTO Filed- April 2, 193e 3 Sheets-Sheet 2 y@ nel CONTROL'SYSTEM FOR FREE STROKE PISTN ENGINES Filed April 2, 1936 3 Sheets-Sheet 3 les Patented Dec. i5, 1939 i CONTROL ,SYSTEM FOR AFREE STROKE PISTON ENGINES Hans Steiner, Winterthur, Switzerland, assigno to Sulzer Frres, Societe Anonyme,

Switzerland `Application April 2,

1n Switzerland Winterthur,

1936, serial' No. '12,359

April 3, 1935 14 Claims. (C1. 60-13) The present invention relates to ireestroke piston internal combustion and air compressor engines, more particularly to such engines in combination with gas consumers, whereby the ini ternal combustion compressor'engine serves as gas producer for said gas consumers, and more particularly to control 'systems for stabilizing the extent of the stroke of the free stroke pistons. If for any reason in free stroke engines the kinetic energy of the power piston is too great when making a compression stroke, the free stroke piston passes over the normal compression end position and the final compression pressure isalso above normal. Therefore also the power produced by the expansion stroke which immediately follows said Atoo great compression stroke is increased; this power is increased bey cause of the increased kinetic energy of the power piston during its compression stroke and also increases because, although the fuel charge is not changed, at increased compression pressure within the combustion cylinder the indicated work of the cylinder increases due to the increased thermal efflcency. Too small kinetic energy during the compression stroke has the opposite effect. For these reasons, changes of the extent oithe stroke of free stroke piston engines are possible particularly when changing the output ofv such engines. f

It is an object of the' present invention to provide a control system for freestroke piston internal combustion'compressor engines, whereby changes of the extent of the piston strokes are reduced oreliminated in order to stabilize the operation of the unified motor-compressor.

A further object of the present invention ref sides in the provision of an apparatus which, in free stroke internal combustion-compressor engines, controls the work produced during the expansion stroke in dependence on the kinetic energy of the power piston making a compression stroke or in dependence on a condition which is dependent on said kinetic energy, for example,

the piston speed.A Said apparatus ispreferablycontrolled and operated in dependence on the position of a power piston at the end of a compression stroke or in dependence on a pressure which depends on the kinetic energy of a power piston making a compression stroke, for example, the pressure in an air buler for said piston.

Another object of this invention is to provide in free stroke internal combustion-compressor engines a. system for stabilizing the movements of the pistons-which prevents increase of the work done during an expansion strokel which.

takes place right after a compression stroke which was too great .due to excessive kinetic energy of the free stroke piston. Further and. other objects of the present invention will-b e hereinafter set forth in the ac- 5 companying specification and claims and shown in the drawings which, by way of /illustratiom show what I now consider to be a preferred embodiment of my invention.

In the drawings: 10 Fig. 1 is a diagrammatic part sectional showing of a plant having two counter-moving free stroke pistons and a stabilizing apparatusv according to the present invention.

Fig. 2 is a diagram showing the change of the 15 thermal efiiciency at a change of the compression volume and compression pressure in `an in-1 of the amount of fuel required for the expansion 2Qv stroke and supplied by a fuel supply control system according to the present invention.

Fig. 4 diagrammatically shows a modification of the control system illustrated in Fig. l. Fig. 5 is a diagram similar to that of Fig. 3 25 and illustrating operating conditions of a plant according to Fig. 4.

Fig. 6 is a diagrammatic part sectional showing of a stabilizing apparatus according to the present invention controlling the amount of com- 30 bustion air and being operated by means of compressed air from an air buffer.

Fig. 7 diagrammatically shows another modification of the'control system shown in Fig. 1.

Fig. 8 shows a vfurther modication of the fuel a5 supply control system illustrated in Fig. 1.

Like parts are .designated by like letters or numerals in all figures of the drawings.

Referring more particularly to Fig. 1 of the drawings: I is the motor-compressor having free stroke, internal combustion power pistons 2 and 3 tofwhich single acting compressor pistons 4 and 5, respectively, are directly connected and which operate, respectively, in the combustion cylinder 6 and in the compressor cylinders 1 and 45 8 which are directly connected to combustion cylinder 6. A synchronizing mechanism comprising two-arm lever 10 and connecting rod 1I connected to one arm of said. lever and free stroke piston 2, 4 and a connecting rod 12 con- 5g nected tothe other arm of said lever and free stroke piston 3, 5 may be provided for assuring counter-movement Aof the pistons. Air compressor pistons 4 and 5 draw air from the out` side `through suction valves 9 and- 9', respec- 55 ever the upper part cylinder 32- is forced down by the pressure of- From. conduit; II,

tively, into cylinders 1 and 8, respectively, and press the compressed air through outlet valves I0 and I0', respectively, into pressure conduit II which may have large dimensions and act as receiver for reducing pressure variations. the air passes through inlet openings I2 into the combustion cylinder 6 where it acts as scavenging and charging air. In combustion cylinder 6, the air which has already been precompressed is further compressed. When power pistons 2 and 3 reach inner dead center position, fuel is injected through injector nozzle 'I3 and combustion begins. The exhaust gas and air` mixture emerges at elevated pressure through outlet openings I3 into the exhaust gas conduit I4 and into the gas turbine I5 in which it produces useful work and from which it emerges through exhaust conduit I6. 'Ihe temperature of the gas and air mixture emerging from cylinder 6 is held within a range suitable for the operation of turbine I5 by providing an excess of precompressed scavenging air.

I 9 is a low pressure fuel pump which is pro-A vided with piston I8 which is operated by cam 20 attached to shaft pressor piston 4 and connected thereto bythe reciprocatingly moving rod mechanism 22. Pump I9 draws fuel from container 23. through suction valve 24 and pushes it into the booster fuel pump 25. Step piston 30 of pump 25 pushes with its lower part the fuel into pressure conduit 3 I whenof piston 30 which moves in the gases compressed in combustion cylinder 6, the compressed gases being transmitted into cylinder 32 by means of conduit 33. Fuel conduit 3| conducts the fuel to the fuel valve 35 which has a fuel needle 'I6 provided with a piston 36 which is forced downwards-as seen in Fig. l-by means of spring 3l. Needle 'I6 is lifted from its seat against the pressure of spring 31 whenever the fuel pressure produced in pump 25 is sufficiently high.

Now follows the description of the apparatus for stabilizing the operation of the internal combustion free stroke piston motor-compressor which controls the work done in combustion cyllinder 6 during the expansion, stroke in dependence on thekinetic energy of the power piston making a compression stroke. The apparatus comprises a fuel by-pass valvemember 38 which is actuated by the bell crank lever 4I which is rotatable around eccentric 30 and is periodically driven by pushing rod t2' connected with compressor piston 4. The position of ec-v centric 40 can be changed by turning lever 44 which is connected thereto. Valve member '38 has a recess 48 the upper edge of which controls'the ow of fuel through bypass channel 41. If, due to a counterclockwis movement of lever di, valve member 33 is lifted upwards against the pressure of spring 45, channel 41 is opened and fuel passes through conduit 43 back into container 23. Spring 45 tends to close the fuel bypass valve; in completelyclosed position, collar 4,6 connected'with valve member 38 restsagainst the casing of the valve.

The position of the power pistons 2 and 3 at the end of their compression strokes depends on the kinetic energy of these pistons when making a compression stroke. At pistons 2 and 3 approach one another more than at medium kinetic energy; at small kinetic energy the space left between pistons 2 and 3 is larger to vseveral pounds pressure 2I which is driven by com- Itons 2, 3 at the end transports the amount of in Fig. 1, pushing rod 42 `dicated by C in great kinetic energy,

than at medium kinetic energy. Great kinetic energy may, for example, be caused' by pressure in the clearance of lthe compressor and/or other return mechanism for the power pistons, which .pressure may for any reason be higher than is normal at a g'iven output of ther compressor and/or said other return mechanism. In twin motor-compressors such as I have shown, for example, in my 1938, in which two power pistons.in two different cylinders are coupled hydraulically, me-

chanically or in another manner and which move in such manner that, when the piston in one cylinder makes an expansion stroke, the coupled piston in the other cylinder makes a compression stroke, too greatkinetic 4energy of the piston in one cylinder may be caused by too great fuel admission into the other cylinder. Too small kinetic energy is'obviously caused at low pressure in the air compressor, in engines of the type shown in my Patent No. 2,115,921, by too small fuel admission in the other cylinder.

Beforeproceeding to describe the operation of the stabilizing apparatus, I explain the diagram Fig. 2 of the drawings. Curve a shows the thermal efficiency of combustion cylinder 6 at various stroke volumes. The ordinates of this diagram indicate the thermal eiciency in per cent. The abscissae, indicate the changes' of thecompression in percent of the normal volume. 'For example, if, at normal position of the power pisof acompression strokeabscissa o in Fig. 2-the thermal eiliciency is the latter is increased, for example, by 1% if the compression by a further inward tons and corresponding,increase ofthe pressure volume decreased by 2% movement of-the power pis-- Patent No. 2,115,921, issued May 3,

sov

in cylinder 6 at the end of `theicompression stroke I of pistons 2 and 3.

The loperation of the stabilizing apparatus can be followed up on diagram Fig. 3. 1n this diagram, the ordinates represent amounts of fuel,

- for example, lbs./hour'or grains per stroke or the like.v The abscissae show the change of the inner dead center position, i. e., the position at g. the end of a compression stroke of the inner end of the power piston by the power pistonsat acertain output at nor- Fuel pump 25 then.

mal operating conditions.

fuel A to fuelvalve 35. At the position of the power piston 2 vshown meets the lower end of lever 4I and by-pass valve 38 begins to uncover channel 4l so that an amount of fuel which is in- Fig. 3 is returned through conduit 49 to container 23 and only the amount of fuel B is injected into combustion cylinder 6 until valve member 38 lupon return of piston 2 is closed again. If power piston 2 exceeds its inner dead center position, for example by 5%. the

period during which channel 41 is opened is also f increased. In order to counterbalance. the ncrease of thermal emciency according to Fig. 2 because of the decrease of the compression end' volume-and increase of the compression pressure of the4 total amount 35, the amount C1 shown in Fig. 3 is returned toV A of fuel supplied to valve,

:ontaine'r 23 and only the amount B1 which is smaller than B is injected into cylinder 6 so that the work of the expansion stroke is not at all or only very little changed. The curve b at the leftv of the zero line o indicates the condition when piston 2 does not reach the normal inner dead center position 58.

A It is obvious that with a stabilizing system as shown in Fig. l the expansion stroke which follows immediately after an abnormal compression stroke with too great or too little kinetic energy is stabilized and further undue increase or decrease of the strokes is effectively prevented.

The operation described sofar takes place as long as the gasrequirements of turbine I5 and the output or load required from said turbine is not changed. If the work demanded from this turbine increases, the speed of the turbine shaft I1 is reduced and eccentric 40 which is connected to governor 5I by means of rods 52 and 53 is turned counterclockwise and the end of lever 4I cooperating with pushing rod 42 is moved to the right and the duration of the periods during which fuel is returned to container 23 is re- 5 duced so that more fuel is supplied to cylinder 8 and more gas is produced for the operation of turbine I5.

The cooperation of the stabilizing apparatusand of the output control is as follows:

* If at a decrease of the work demanded from turbine I eccentric 40 is turned clockwise, the end of the arm of lever 4I which cooperates with the pushing rod 42 is moved to the left. By-pass valve 38 is then alreadyn opened when power piston 2 reaches a position which is to the left of the position in whichsaid piston is shown in Fig. 1 and the duration of opening of valve 38 and the amount of fuel returned to container 23 is increased; the work done during the expansion stroke is then reduced. If only the amount of fuel is changed' and the pressure of the charging air introduced into cylinder E remains the same, the operation is as characterized by curve c in Fig. 3, whereby an amount of fuel C2 is returned to tank 23 at the position of the power piston designated by O and the amount of fuel B2 is injected into cylinder 6. At a simultaneous change of the charging pressure and of .the amount of fuel supplied the zero line in Fig. 3 is moved to the left, for example, to O1 at increased charging pressure so that. the amount of fuel injected corresponds to curve d whichvis drawn parallel to curve c.

Instead of providing eccentric 40. and using bypass valve 38 for stabilizing as well as gas output control, lever 4I may have a fixed fulcrum 19 and the supply of fuel in proportion to the load conditions on turbine I5 is controlled as shown in Fig. 4. Suction valve 24 is provided w'th a rod 14 resting on arm 21 and pressed thereto by spring 15. Arm 21 rotates about eccentric 28. When arm 21 is rotated counter-clockwise, valve 24 is opened, for example, near the end of the compression stroke of piston I8 and supply of fuel by pump I9 is interrupted. Governor 5I is connected by means of rodl 52, bellcrank lever 11 and rod 18 with arm 28 of eccentric 26 as is shown in Fig. 4. The amount of fuel supplied by pump I9 and delivered to cylinder B is thus made dependent on the load of turbine I5. The diagram Fig. 5 shows`the operating conditions which are eifected by an arrangement -according to Fig. 4 of the drawings. In this diagram, ordinates and abscissae represent the same values as in diagram '(8 Fig. 3; Stabilization ytakes place according t0 curve e. If the load onturbine I5 is reduced, lessfuel need be supplied to cylinder 5 and the fuel supply by pump I9 is reduced from the value -represented by ordinate A1 to the value represented by ordinate Az. Valve 38 permits return 5 of the fuel amount C to tank 23 and the fuel actually injected is reduced from the value Ba to value B4. The work of thevexpansion stroke is therefore also reduced.

In the arrangement according to Fig. 6, the 10 inner parts 54 and 54 of cylinders 1 and 8', respectively, serve as air buffers. In this case, the condition depending on the kinetic energy of the power pistons is the pressure within said air buffers. The stabilizing apparatus comprises pis- 15 ton 55 in cylinder 5B which communicates with buffer 54 by means of conduit 62, spring 51 which holds the position of piston 55 against the air pressure in conduit 82, and valve casing 59 containing valve 58, the stem 80 of which is conm nected to piston 55. Valve 58 controls the exit of the contents of cylinderG through conduit 6I which connects valve casing 59 with the intake openings I2. The tension of spring 51 can be adjusted by manipulation of screw 63. The apparatus according to Fig. 6 operates as follows: Piston 55 opens valve 58 whenever4 the air pressure in air buffer 54 reaches a predetermined value which can be adjusted by means of screw'63. At the normal position of power piston a0 3 at the end of its compression stroke, the pressure,

in chamber 54 is higher than said predetermined value and valve 58 is opened and a small amount of the contents of cylinder 6 is'releved. If the inner dead center position of free stroke piston 3,5 is further out than normal due to too little kinetic energy, valve 58 is opened less because of the smaller pressure in buffer 54 and less contents are allowed to escape from cylinder 5. At

too great kinetic energy, the inner dead center 40 position of piston 3,5 is further inwards andvalve 58 is further lifted and more contents of cylinder 8 are removed therefrom so that the compression pressure at the end of the compression stroke of pistons 2 and 3 is reduced and therebythe energy 45 developed at the following expansion stroke. The pressure in cylinder 6 at the end of the compression strokes of the power pistons 2 and 3 is thus maintained and at constant fuel supply also the workof the expansion strokes is maintained al- 50 most or completely constant, no matter. what kinetic energy may bein the pistons when making an inward stroke.

The more piston 3, 5 moves inwards, the longer and the more valve 58 is opened and the more 55 contents escapes from cylinder 6. Also at normal inner. dead center position of piston 3, 5, a certain amount of the contents of cylinder 6 isipermitted to escape so that, at too little kinetic energy of piston 3, 5, this amount can be still further re- 60 duced and operation of the piston be stabilized at all operating conditions.

In Fig. 'I an arrangement is shown in which,v instead of providing by-pass valve 38, the horizontal arm--as seen in Fig. l--of lever 4I is con- 65 nected by means of rods 8I and 82 with lever 28 of `eccentric 26. A lever 83 is arranged between rods`8I and 82 'in order to reverse the direction of movement of rod 82 as compared with that of rod 8I. Adjusting means 84 are 70 provided in rod 82 for setting the mechanism, to suit operating conditions. Also' lever 83 may be so constructed that the leverage can be changed. In the embodiment of my invention shown in Fig. this is done by providing in one is connected with arm of lever 89 a y it is operatively connected plurality of holes 99 to which rod 82 can bev individually connected. If, by changing the output of fuel feed pump i9, instead of correcting the expansion stroke which immediately follows an abnormal compression such an abnormal compression stroke is corrected, it is advisable to adjust the mechanism in such a manner that the amount of fuel `delivered by pump |9 is excessively decreased or increased in order to counterbalance the effect of the intermediate excessive or too small exginning as well as the end of an injectioncan be changed lwith respect to the time in which a free stroke piston reaches its inner dead center position. Similarly, as was describedvin connection with Fig. 1, fuel pump I9' is provided with a pump piston I8 vwhich is operated by a cam 28 mounted to a shaft 2|. To this shaft a lever 85 is so connected that its position can be changed with respect to shaft 2|. Lever 85 piston 4 by means of rodsv22' and 81 and bellcrank levers 86 and 88. By adjusting the position of lever 85 with respectto shaft 2|, the action of pump piston I8 can be timedv'with respect to the 2, 4. Pump I9' is provided with a suction valve 24' which correspondsI to the suction valve 24 in Fig. 1 and is also driven by plunger I8 to which by two-arm lever 21. The latter swings about eccentric 26', tion of which can be changed by moving arm 28. Arm 28 is operatively connected with sleeve 89 of turbine governor 5| so that it swings to the right when the speed of the turbine goes up. Valve 24 is thereby lifted and less vfuel pushed into conduit 3|. Pump |9 is further provided with a fuel return valve 98 which is reciprorcatingly operated'by lever 9| about point 92 and is moved up and down by means of rod 93 which is connected to the horizontal arm-of bellchank lever 4| which corresponds to lever 4| of Fig. 1. The vertical arm of lever 4|'A is operated by pushing rod 42 connected to piston 91 which operates in a cylinder higher the pressure in buffer 54, the the right are piston 91 and rod 42 moved. Point 92 rests on lever 94 which swings about stationary fulcrum 95 and vis movably connected to and reciprocatingly moved by plunger |8. T he further piston to the right the more are lever 9| and valve 90 lifted and the more fuel is rreturned through conduit 96 to fuel storage tank 23 and the less fuel is supplied to injection valve so that the fuel available for effecting an expansion stroke whichfollows after an abnormally great compression stroke is reduced.

While I believe the mentsv of my inventionto be preferred embodiments, I wish it to be.

skilled in the vart.

I claim: 1. A control system vfor the supply of fuel 'to second expansion stroke after' movement of piston which swings `means adapted to return internally connected with air4 buler 4 and rod 42 move' above described embodifree stroke piston internal combustion engine having a-power piston, said system including fue by-pass means, connecting4 means adapted tl operatively connect said power piston and sait by-pass means whenever said piston approache: the end pression stroke.

2. A fuel supply control system for free stroke piston internal combustion vengines ,having 'a power piston, fuel storage means, means for supplying fuel from said storage means to said engine, fuel return means for returning fuel from said supply means to said storage means, said return means being operatively connected with said power piston,'whenever said power piston makes a compression stroke, and being responsive to the extent of the compression stroke of said power piston, whereby the amount of fuel supplied to said engine is made dependent on the extent of the compression stroke of said free stroke power piston.

3. A fuel supply vcontrol system for free stroke piston internal combustion engines having a power piston, fuel supply means, fuel byfpass means for by-passing fuel to said fuel supply means, said by-pass means being operatively connected with said power piston, wheneverv it approaches the end of its compression stroke, and being responsive to the extent of the compression stroke of said power piston, whereby the operation of said by-pas's means and the said engine is made of said free stroke power piston at the end stroke.

of its compression 4. A fuel supply control system for free stroke 'Y piston internal combustion engines having aV connected with said piston, whereby the fuel supply is made periodically and synchronously with the movements of said piston, fuel return fuel from said supply means to said storage means and to determine the end of the fuel supply periods, said return means being operatively connected with said power piston whenever it approaches the end of its compression stroke and being responsive to the extent of the compression stroke of said system for the supply 'of' fuel tohaving a power piston, said system including fuel by-pass means which are temporarily operatively connected with said power piston at the end of its compression stroke and responsive to the extent of the'compression stroke of said power piston and adapted to decrease the amount of the amount of fuel great Yextent of `the compression stroke.

6. The combination of a unified internal combustion and compressor engine having a free stroke piston, an exhaust gas machine having a Speed) governor and being connected vfor flow with and receivingexhaust gas as operating medium from said engine, and'combustion material supply control means which are directly operatively connected with said engine and with said speed governor for controlling the supply of combustion materials to said engine and production of exhaust gas in dependence on the load'on said gas machine.

,'l. The combination of a free stroke piston internal combustion engine having a free stroke piston,'an exhaust gas machine having a speed responsive governor and being connected for gas now with and receiving exhaust g as as operating medium from said engine, and combustion material -supply control means temporarily operatively connected with said free strokel piston at the end of its compression stroke and being responsive to the extent of the compression stroke and being also directly connected with said governor for controlling 'bustion materials to said engine in dependence on the extent of the compression stroke of said free stroke piston and in dependence on the load on said exhaust gas machine.

8. The combination of a free stroke piston internalcombustion engine having a free stroke piston, an exhaust gas machine having a speed responsive governor and being connected for 'gas ow with and receiving exhaust gas as operating medium from said engine, and combustion mate- A rial supply vcontrol means comprising a fuel pump dependence on which is connected with and operated by said free stroke piston, said pump having a fuel flow control valve which is operatively connected with said governor, whereby the supply of combustion material to said engine is controlled in dependence on the stroke of said free stroke piston and on the load on said gas machine.

9. A control system for the supply of combustion material for free stroke piston internal combustion engines having a power piston and combustion material supply control means cooperating abbutingly with said power piston makes a compression v of combustion material supplied iscontrolled in dependence on the stroke of said free stroke power piston when making a compression stroke.

10. A control systemfor the supply of combustion material for free stroke piston internal combustion engines having a power piston and combustion material supply control means cooperating abuttingly with said power piston whenever said power piston approaches the end of its compression stroke, whereby the amount of combustion material supplied 'is controlled in the position of said free stroke power piston at the end of its compression stroke.

11.`A free stroke piston engine having a free stroke piston, fuel supply means connected with and operated b'y said piston and being connected for fuel now with said engine, a fuel flow control valve connected with said supply means and being adapted to control the amount of fuel supsaid engine, an exhaust gas consumer flow with said engine and being adapted t'o be operated by the exhaust engine, load responsive means dithe supply of comp trolled in dependence on the load rectly connected with said gas consumer` and being directly responsive to the load on said consumer. and being connected with and operating said control valve in response to the load on said gas consumer, whereby the amount of fuel supplied to said engine. is controlled in dependence on the load on saidl consumer.

`12. The-combination of a free stroke piston engine having a free stroke piston, fuel supply means connected with and operated by said piston and being connected for fuel flow with said engine, a fuel intake valve connected with said supply means and being adapted to control the amount of fuel supplied to said engine, an exhaust gas consumer connected for exhaust gas flow with said engine and being adapted to be operated by exhaust gases of said engine, load responsive means directly connected with said. gas consumer and being directly responsive to the load in said consumer, and-being connected with and operating said intake valve in response to the load on said gas consumer, whereby the amount of fuel supplied to said engine is conon said consumer, and a fuel relief valve connected -with said supply means and being temporarily opera.- tively connected with said piston whenever said piston approaches the end of a compression stroke and being adapted to be opened at excessive extent of a compression stroke of said piston, whereby fuel is relieved and not'l suppliedv to said engine.

13. A free stroke piston enginehaving a free stroke piston and comprising a fuel pump which is connected with and operated by said -iree stroke piston and which is provided with a reliefv valve, mechanical means temporarily connecting vsaid relief valve with saidzfree stroke piston whenever said piston makes a compression stroke and being adapted to open said valve when said piston approaches the end of al compression stroke, whereby fuel is relieved from said pump and the fuel discharge of said pump is reduced when the compression stroke of 'said piston is excessive, and adjusting means connected with said rst mentioned meansl for adjusting the extent of opening of saidvalve. Y

14. A free stroke piston engine having a power cylinder and a free stroke power piston operating therein, fuel supply means connected with said power cylinder and comprising fuel supply control means, a compressor cylinder connected with said power cylinder and having a compressed air producing and a control chamber, a double acting compressor piston 'connected with said power piston and operating in said compressor cylinder and dividing said cylinder into said two chambers, apressure responsive means connected with said fuel supply control means and with the control chamber of said compressor cylinder and being 

